Across systematic reviews and meta-analyses, MSC treatment appears consistently safe and well tolerated. Most adverse events are mild and transient, such as headache, fever, fatigue, back pain, or transient infections, while serious complications are rare and often related to the injection procedure rather than the cells themselves (Vaheb et al., 2024; Islam et al., 2023; Oliveira et al., 2019; Uccelli et al., 2021; Yim et al., 2019).
This safety profile is consistent across different MSC sources—including bone marrow, adipose tissue, umbilical cord, and placenta—and routes of administration, such as intravenous or intrathecal (Sheikhi et al., 2025; Islam et al., 2023; Dahbour et al., 2017; Oliveira et al., 2019; Shokati et al., 2025; Ghareghani et al., 2024; Riordan et al., 2018). Best practices emphasize careful patient screening for comorbidities or infections and use within formal clinical trial frameworks (Vaheb et al., 2024; Sheikhi et al., 2025; Shokati et al., 2025; Kvistad et al., 2022).
MSC therapy in MS shows modest and variable efficacy. Meta-analyses report small average improvements in disability (EDSS changes around –0.2 to –0.4 points) or disease stabilization rather than dramatic recovery. Approximately 30–40% of patients improve, a third remain stable, and 15–20% may worsen following MSC therapy (Vaheb et al., 2024; Islam et al., 2023; Yim et al., 2019; Shalhoub, 2023).
The MESEMS multicenter randomized trial confirmed safety but found no significant effect on MRI gadolinium-enhancing lesions at 24 weeks, highlighting limitations in anti-inflammatory efficacy. Other controlled and uncontrolled studies, however, show reduced disease activity and some functional gains, particularly in progressive MS with active disease (Petrou et al., 2020; Dahbour et al., 2017; Oliveira et al., 2019; Shokati et al., 2025; Ghareghani et al., 2024; Riordan et al., 2018).
Several protocol features appear linked to better outcomes:
Current guidance supports MSC use only within rigorously designed clinical trials, with:
Overall, MSC therapy for MS appears to stabilize disease and provide modest functional improvements, but there is no definitive evidence that MSCs outperform optimized conventional therapies in large randomized trials (Maji et al., 2025; Kvistad et al., 2022; Yim et al., 2019).
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